.tab{
  width: 500px;
  height: 500px;
  margin: 50px auto;
  border: 1px solid #000;
}
.tab .nav{
  height: 50px;
  border-bottom: 1px solid #000;
}
.tab .nav-item{
  float: left;
  width: 33.33%;
  height: 100%;
  text-align: center;
  line-height: 50px;
}
.tab .nav-item.current{
  background-color: #000;
  color: #fff;
}
.tab .page{
  height: 450px;
  overflow: auto;
  padding: 15px;
  box-sizing: border-box;
}
.tab .page img{
  width: 100%;
}